1. Field of the Invention
The present invention relates to storage apparatuses for storing images or the like transferred via a network.
2. Description of the Related Art
A known monitoring system is available in which a camera is placed at a remote place, and an image shot by the camera is transferred to a terminal via the Internet or the like and displayed on a display or accumulated in a storage medium.
A technique similar to such a monitoring system is described in Japanese Patent Laid-Open No. 07-327214. In this document, a display interval between frames is extended when data processing is delayed due to some reasons, and, in the opposite case, the display interval is shortened.
In the monitoring system, when storing an image transferred from the camera in a secondary storage medium such as a hard disk drive, the terminal, which takes into consideration the time required to write the image into the storage medium, stores the image in a temporary memory and then in the storage medium.
However, when the terminal simultaneously receives images transferred from a plurality of cameras, the temporary memory may be short of capacity to store all the images. In such a case, image frames may not be able to be stored in the secondary storage medium for a long period of time.
To overcome the insufficiency in capacity of the temporary memory, image frames stored in the temporary memory may be decimated. However, when one central processing unit (CPU) performs a plurality of operations on the received images, such as storing the received images and performing motion detection on the received images, the load of these operations causes a delay in storing the images. As a result, the capacity insufficiency cannot be fundamentally overcome.